Organic silicone polymers are useful in a variety of applications. A group of these materials, silicone polymers formed using trifunctional silanes as cross-linkers, have multiple T-junctions. These polymers are, when properly derivatized, used as the bases for polishes, water repellant coatings for fabrics, and contact lens materials. A subset of these materials is known as RTVs (room temperature vulcanizable) polymers. (It is also possible to cross-link basic polymers formed from bifunctional silane to obtain X branches through the use of tetrafunctional silane compounds.)
In some applications, it is desirable to include, in the polymer, materials which will serve a labeling or indicating function, or which will simply color the material as in the case of colored contact lens materials. For example, U.K. Patent Application 2,132,348A discloses a method and apparatus for determining the presence of oxygen which employs a sensor material embedded in a silicone resin. The resin is impermeable to quenchers other than the oxygen analyte, which interfere with the determination, and thus offers an advantage over use of the sensing material directly. Similar materials are available for the detection and quantitation of other atmospheric components such as carbon dioxide or for measurement of, for example, pH or other specific analytes.
The present systems which employ silicone polymer supports for the detecting or coloring material suffer from the disadvantage that the reagent is not covalently bound to the polymer and therefore is both difficult to control as to concentration and is subject to instability and leakage. One approach to solving these problems is to link the detecting or other desired material covalently to the polymer support.
Others have applied this general approach using different, non-silicone, polymeric backbones. For example, U.S. Pat. No. 4,194,877 to Peterson discloses the preparation of a dye/acrylic copolymer as a pH sensor. Similarly, U.S. Pat. No. 4,468,229 discloses contact lens compositions wherein reactive dye materials are covalently bound to the monomeric starting materials which are then polymerized. In this case, the resulting polymer is basically a highly substituted polyethylene backbone; that is, for example, the basic polymer is of a hydroxyalkyl ester of an unsaturated acid, most commonly hydroxyethyl methacrylate. Applicants are unaware of any general method of binding indicator reagents or other desired complex reactive materials covalently to silicone polymers.
Since the properties of silicone polymers are advantageous in many applications, it would be useful to have available the corresponding covalently labeled materials having silicone backbones. The present invention provides such methods and materials.